Frequencies for phazplac variable in parkwork dataset :

  hazardous |
  materials |
involvement |
/placard-hm |
  2 placard |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,142       99.65       99.65
          2 |          2        0.17       99.83
          8 |          2        0.17      100.00
------------+-----------------------------------
      Total |      1,146      100.00

by Jean Roth , jroth@nber.org , 22 Oct 2016